Process of corrugating sheet metal



Feb. 29, 1944. w, IMATLAT 2,343,126

PROCESS OF CORRUGATING' SHEET METAL Filed April 9, 1942 2 Sheets-Sheet 1 WHZ. o

65, fifjifallat INVENT'OR.

Feb. 29, 1944. G. w. MATLAT 2,343,126

PROCESS OF 'CQRRUG'ATI'NG SS'HEET METAL Filed April 9, .1942 2 Sheets- Sheet 2 GLH IMaZZaZ IN V EN TOR.

Patented Feb. 29, 1944 UNITED STATES PATENT. OFFICE 2,343,126 7 rnocnss or CORRUGATING SHEET METAL Gustav 'w. Matlat, Washington, D. 0.

Application April a, 1942, Serial No. 438,313

2 Claims.

This invention relates to a process of corrugating metals such as sheets or strips of aluminum, aluminum alloy, stainless steel, etc.

In various industries but more especially in the airplane industry, corrugated sheets of metal are used extensively for structural purposes, especially for wings and tail surfaces. It is essential, however, that the corrugations be accurately formed so that they comply with the design form of the corrugation. This compliance with the design form is necessary for two vital reasons. ing member, the corrugated sheet or strip will, by its true conformity to design form, retain its full structural integrity. Secondly, that as a formed part, mating with related parts, its true conformity with the design form will insure definite response to fitting, bolting, riveting, or other fastening means. This facility of installation, made possible only by the new process, does contribute to an absolute minimum of rejected Firstly, that as a load-carryparts, reduces the volume of hand work required I in assembly, and ultimately cuts the manufaclurin cost of the finished article. Obviously unless the sheets or strips are accurately corrugated, the structural integrity and the uniformity are lacking, and the. assembly thereof accordingly sufiers in quality and in production speed,

Another important factor to be considered in the formation of corrugated sheets wherein accuracy is demanded, is .the inherent resiliency or spring-back of the metal being operated upon.

Unless this spring-back is accurately estimated in advance, a sheet of metal, after being accurately corrugated, will readjust itself so that the proper shape of the corrugations will not be retained.

the metal to flow evenly during the bending operation so that the sheet will be of equal thickness throughout its corrugated portion. Here, too, the structural integrity of the corrugation is preserved since the forming method employed has inflicted no stretching of the metal in any place whatsoever.

' A further object is to provide a process which will speed production of accurately corrugated sheets. The accuracy and the uniformity of product by this new process has heretofore been unattainable by current methods. By virtue of these two qualities which are are afforded by the new process, production is facilitated to a point where it has been possible to produce as many as eighty accurately. corrugated sheets in the same time heretofore required for the production of one sheet by the well known punch and die method, so that the cost of production is materially reduced.

With the foregoing and other objects in view which will appear as the description proceeds, the, method consists of certain novel steps hereinafter mor fully pointed out and claimed, it being understood that changes may be made therein without departing from the spirit of the invention as claimed.

s In the accompanying drawings the several steps in the method and the means utilized for performing, the same, have been disclosed.

is carried out.

tions of two rolls with a corrugated plate therein preparatory to increasing the, depth of the corrugation.

In carrying out the process constituting the present invention, but two steps are involved in the whole procedure. The sheet S is preformed transversely by the rolling action of a rotatable toothed roll upon, and in cooperation with a matching toothed bed plate or table, the teeeth of both members being of such design as will first insure an aggregate engagement of no less than two teeth at any'and all times of sheet forming, and second, that in the formed'sheet,

2 after the "spring-back has taken place, the produced corrugation will be of the proper shape and proportions. In Figure 1 the stationary toothed bed plate or table has been indicated at l while the rotatable toothed roll has been indicated at 2. It will be apparent, by referring to said figure, that after a sheet S has been deposited 2 as indicated at 3. Thereafter, as the roll 2 ad vances, the partly depressed portion of the metal is fully depressed into table I as indicated at 4. as the metal is not abruptly shaped, as by means i of a reciprocating punch, but is gradually brought to the position 4 following a preliminary depression at 3, the metal is afforded an opportunity to become evenly distributed so that in the finally shaped plate, the sheet will be of uniform thickness throughout the extent of the corrugation and will not be thinner at one place than at an- "other due to a drawing action such as would be effected should the plate be subjected to a punch ing operation.

It is intended, by means of the first stage of the method, to bring the plate S approximately to its ultimate shape. found that the plate cannot be accurately formed by the one operation. Instead it must be subsequently treated to insure the accuracy so necessary in speedy production of airplane structures,

etc.

For the purpose of carrying out the second or -finish forming stage of the process, a means such as shown in Figures 2 to 6, inclusive, is preferably used. This includes only one pair of rolls between which the preformed corrugated sheet is adapted to be fed longitudinally of its corrugations. One of these rolls, indicated at Fig. 5, is mounted for rotation about a fixed center 6 while the top roll I is mounted to rotate about a center 8 capable of moving in an are about the center 6 as an axis. Both of the rolls are cormgated in their forming faces to give the preformed plate its final finish so that after the plate has passed from between the rolls and has completed its predetermined spring-back, the

corrugations will be of the size and proportions essential to insure accurate and ready incorporation of the formed sheet in the structure to be built. .It will be noted by referring to the drawings that the rolls and I can be adjusted to increase both the width of the corrugations and their depth. The width of the corrugations can be increased by inserting thin shims 9 between the adjacent disk-like rings l0 forming the respective rolls. Obviously by using shims of different thicknesses, or multiples thereof, the widths of the corrugations can be quickly changed at will. The shims can be slotted or forked as shownso that they can be applied or removed from the shafts I l of the rolls without disassembling said rolls. The rings, and the shims therebetween, if the latter are used, can all be clamped together tightly by nuts or similar devices screwed on the shafts but which have not been shown. Obviously by removing the shims from between the disk-like rings III the corrugations can be reduced in width as shown in Figure 3 from the size shown in Figure 4.

In practice it has been.

Following adjustment of the rolls for the purpose of producing finished corrugations of predetermined wldths in the plates S, the roll I is adjusted angularly'so as to increase or reduce the vertical distance between the levels of the two axes 6 and 8. For example if it is desired to increase the depth of the corrugations in the plate, the axis 8 can be adjusted angularly as indicated in Figure 5, so as to move it from position a to position b. This will result in a corresponding reduction in the size of the horizontal pass between the rolls so that if the preformed corrugated plate S is fed between the rolls in the shape shown for example in Figure 6, wherein clearances are provided between the corrugations and the rolls 5 and I, an angular adjustment of the roll 1 sufiicient to compensate for this clearance will result in forcing the corrugations the maximum distances into the rolls. Thus the corrugations will be formed of accurate depth and width by being subjected to the action of the rolls 5 and I as the corrugations of the sheet move longitudinally between the rolls.

Importance is attached to the fact that the first stage of this process is designed to maintain constant the metal thickness following the initial corrugation so that the structural qualities of the gauge of the sheet stock will be preserved. This initial forming of the sheet produces transverse corrugations therein. When the sheet is fed between the rolls 5 and 'I it is moved longitudinally of the corrugations, passing preferably over a corrugated idler roll l3 and a flat table l4. As the sheet passes between the rolls the contours of the ridge and groove are refined, trued and sized .up, and the pitch of the grooves, singly and totally, is uniformly achieved. This result is obtained because of the adjustments possible with the rolls 5 and I as heretofore explained, it being understood that the roll l3 and the table I 4 will compel the corrugated sheet to travel straightforwardly or longitudinally of its corrugations independently of any angular adjustment of roll 1 relative to roll 5 which might occur.

By following the method herein described it is possible following the determination of the spring-back" factor of themetal, to adjust the apparatus accurately so that all of the finished sheets will be of the correct contour, pitch, depth 'and gauge throughout.

What is claimed is:'

1. The process of accurately corrugating a cold sheet of metal and compensating for spring bac in the sheet, which includes the step of feeding the sheet endwise between cooperating corrugating means to shorten the sheet and form corrugations extending along straight lines transversely of the sheet, thereby to distribute the metal evenly in preformed corrugations approximating the predetermined ultimate contours of the finished sheet and without appreciably changing the surface area of the sheet, and thereafter feeding the corrugated sheet sidewise along straight lines between a pair of corrugated rolls to simultaneously reshape the transverse contours of all of the preformed corrugations and bring them to a predetermined depth and transverse contour, and maintaining the corrugations along straight lines longitudinally thereof during and after the reshaping operation.

2. The process of accurately corrugating a cold sheet of metal and compensating for spring back. in the sheet, which includes the step of feeding the sheet endwise between cooperating corrugating means to form corrugations extending transversely'of the sheet, thereby to shorten the overall length of the sheet and distribute the metal in preformed corrugations approximating the predetermined ultimate contour of the finished sheet, and thereafter feeding the shortened corrugated sheet sidewise along straight lines only between a pair of corrugated ing operation.

- GUSTAV W. MA'ILAT. 

